Bidwell's Ghost

Bidwell’s ghost is a visual phenomenon characterized by the after-images that the eye and brain experience following exposure to bright flashing lights. The negative afterimages are like ghosts since they trail behind and take the form of the original image. This is a usual phenomenon that all of us have probably experienced at rock concerts or nightclubs where alternating flashing lights are expected. This term is attributed to Shelford Bidwell, an English physicist and inventor.